Contemplating a 4BT swap into my '99 3.9L, (AX-15, 231HD). In doing the research I'm trying to determine the weight difference between the 4BT and the 3.9L to see how much I'm going to have to beef up the front end. Anybody have access to the dry weight for the 3.9L? I can't find it anywhere! Engineering dimensions would be nice too, but not necessary, yet...
More to come...and thanks for the help guys - I learn lots on here!

 

you are going to have to swap the whole front axle out for a dana 40 or 60 most likely. The 4bt is a pretty heavy engine for its size

 

Brought home my 4BT today - leaving for one of the world's faraway sandboxes in a few days... she'll be here when I get home though! Hopefully I'll have time over there to continue researching what needs to be done to make the swap go smoothly.

 

You should post up some pics of the motor. I'd love to see this swap. Everyone always says they are going to but never pull through.

Marines? If so, thanks for your service man, you guys have more courage then anyone and I could never do what you do..

 

I'll document the build as I get working on it - only a couple month deployment this time around so maybe this spring...? Air Force - and yeah, I know, it is hardly a deployment compared to what some of our guys go through, staying a year or more at a time... I honestly don't see how those guys leave for that long at a time!

 

Anyone in the service gets my upmost respect.

 

4 bt is a tall engine and weighs about 500lbs more that the 3.9 if you have a auto you will run into computer issues with shifting and you could have issues with adapting too
and oil pan clearances and hood issues I put a Nissan rd 28 in a jeep Cherokee took a shoehorn to do it was a good ride but was also too heavy for that little truck not to tell you what to do i would use a Isuzu turbo smaller and lighter and don't confuse the horsepower of a diesel with that of a gas a diesel can do more with less the 4bt is a fantastic motor just like its bigger cousin the 6bt which dodge has installed in the big trucks for years but it is a heavy engine I have a isuzu in mind for mine when the engine blows if you want some real insite on issues drop me a line way too much to go into here I have done this and with the newer trucks it is a good idea but the computer will have to go by by and if your state does emissions then you are in a pickle

 

the isuzi diesil is a great engine, and they did but some type of isuzu turbo diesil in dakotas but were only sold in south america.

See if you can find one with the tranny on ebay because its almost a direct fit!

 

I think the one I am thinking of is a 4le2t it produces in the 90 hp range I have one on a engine stand will have to look at the book the Governor spring would have to be changed if my memory is correct it came out of a street sweeper